The amount of light that can be injected directly from a semiconductor laser into a cleaved single mode fiber is limited by the modal mismatch of these two waveguiding structures. This limitation is due to the modal mismatch between the highly diverging laser beam and the small numerical aperture of the fiber. The laser spot size is typically around 1 .mu.m while that of a fiber is around 10 .mu.m. This disparity limits the coupling efficiency between these two devices to about 10%, if perfectly aligned. In many communication systems there is a need for high optical power at a low laser drive current. In particular, in the local loop of the telephone system one needs to split the optical signal and send it to multiple of customers. The coupled power may limit the number of splits possible. A number of techniques have been devised to increase the coupling efficiency of light into a fiber. These include modifying the shape of the fiber end (tapering or flame lensing or both) so that the modal mismatch is reduced. However, the coupling efficiency is improved at the expense of very tight alignment tolerances. Uptapered fibers have been also shown to perform well, but there is a need for an additional lens between the laser and the modified fiber. This makes the assembly difficult. Still another approach is to modify the laser structure so that it has a tapered output section thus increasing the laser spot size in the junction plane. This technique increases the coupling efficiency, but only for spatially fabricated lasers. Moreover, the performance characteristics of these lasers may not be adequate for the intended purpose. A yet further approach involves positioning a tapered waveguide with a graduated index of refraction between a laser and the fiber or the technique disclosed by Shani et al. whereby two nested waveguides, one matching the laser mode and the second matching the fiber mode are utilized. These approaches work well, however, they are complicated and difficult to make.